This invention relates to an apparatus and method of producing synthesis gas from biomass. The invention furthermore relates to computer processing product for performing the method of the invention and the use of the produced synthesis gas.
It is well known to produce synthesis gas which is a mixture primarily consisting of CO and H2 from fossil materials such as coal and crude oils, see U.S. Pat. No. 5,637,259.
However, since such raw materials are available only in limited amounts scientists have lately focussed on the production of synthesis gas from renewable raw materials such as raw materials derived from plants e.g. biomass.
Examples of such biomasses are wood, straw, waste paper, municipal solid waste and mixtures thereof.
It is well known that by heating wood materials to a high temperature such as 800° C. under anaerobic conditions the wood materials give off gaseous and liquid substances leaving behind charcoal. When the charcoal is reacted with carbon dioxide and water at high temperatures synthesis gas is formed. Synthesis gas can also be produced by cracking tar materials.
The composition of the produced synthesis gas can be controlled e.g. by separation of carbon dioxide see e.g. U.S. Pat. No. 6,133,328.
U.S. Pat. No. 6,133,328 describes a three step method of producing synthesis gas from biomass. In the first step the biomass is dried to form moisture free biomass.
In the second step the biomass is burned under anaerobic conditions to form charcoal and the flue gasses thus produced are passed through heat storage means to heat said means to an elevated temperature. In the third step water is passed through the hot heat storage means and evaporated to form hot steam which is passed through the charcoal formed in the preceding step so as to form synthesis gas.
EP 971017A2 discloses a method and a device for converting solid fuel into a lean gas having low calorific value for direct use in an internal combustion engine. The fuel is heated to a temperature effecting pyrolysis and subjecting a further treatment at a temperature ensuring that long-chain and/or poly(cyclic) hydrocarbon compounds are cracked thermally.
It is an object of this invention to provide a simple, environmental friendly method and apparatus for producing synthesis gas from biomass.
It is a further object of this invention to provide a method and apparatus for producing synthesis gas, which are less energy consuming than prior art processes.
Another object of this invention is to manufacture synthesis gas for use in the synthesis of chemicals e.g. methanol.
Yet another object of this invention is to manufacture synthesis gas for use as fuel, e.g. for internal combustion engines or fuel cells.
Still another object of this invention is to provide a method for the production of synthesis gas containing only an insignificant amount of contaminants.